XV. LYCOrOOIACEAE. 



Terrestrial or epiphytical, rarely subaquatical. Primary axis (main 

 stem, rhizome) short or elongate, rarely tuberous. Leaves simple, mostly 

 small, rarely long-subulate, approximate or remote, not laterally connected, 

 rarely tufted at the base of a short, unbranched, naked stem. Sporophylla 

 consisting of unaltered leaves all down the stem and branches or more 

 or less modified and aggregated in dense, terminal or rarely lateral spikes ; 

 sporangia 1-locular, 2-valved, placed singly in the axils of the sporophylla ; 

 spores of 1 kind, rarely 2-lateral, mostly globoso-tetrahedral, with the 

 upper part broadly trigono-pyramidal with 3 ribs radiating from the apex 

 and the lower part rounded and punctulate, foveolate, aculeate or reticulate. 



lOS. LYCOPODIUJM, lAnni. 



Main stem not tuberous; secondary axes (stems, shoots) elongate, 

 erect, ascending, scandent or pendulous, mostly branched; steles solitary, 

 central, composed of few to many regularly or irregularly arranged, free 

 or connected groups of tracheide bundles. Leaves not placed in a basal 

 tuft, mostly occupying both stem and branches, sometimes more or less 

 wanting in the older portions of the shoots, mostly multifarious (i. e. 

 isomorphous and placed in more or less dense whorls or spirals), sometimes 

 quadrifarious (i. e. isomorphous and arranged in 4 rectangularly decussate 

 rows), rarely platystichous (i. e. heteromorphous and placed in 4 — 6 rows 

 with those of the lateral rows more or less broadly spreading or erecto- 

 patent and those of the dorsal and [or] ventral rows smaller, linear, more 

 or less adpressed, so as to form rather flattened or bilateral stems and 

 branches). — Engl. & Prantl, Nat. Pfl.Fam., I^ fig. 365, 368, 37L 



Cosmopolitan, except in large, dry, sandy or rocky regions. 



Arrangement of the sections and groups. 



§ 1. UROSTACHYS. Monopodially branched main stem wanting, the shoots 

 solitary or fascicled, dichotomous (i. e. 2-furcate, with the branches 



